1. Field of the Invention
The present invention relates to a lens apparatus, and particularly to a lens apparatus removably attached to a camera body of a TV camera, etc., in which transmission of various signals with the camera body can be provided in both a serial transmission system (serial communication) and a parallel transmission system (parallel communication).
2. Description of the Related Art
A lens apparatus removably attached to a camera body (camera head) of a TV camera for broadcasting is also electrically connected to an electric connector of the camera body and communicates various signals with the camera body. A transmission scheme by which the camera body communicates signals with the lens apparatus may be a system using a serial transmission system, a parallel transmission system or both systems. In the serial transmission system, a plurality of pieces of information is transmitted through one line (signal line) in a form of digital serial signal, and in the parallel transmission system, a plurality of pieces of information is classified by a type of information as a low (L) level signal and a high (H) level signal, or converted into an analog signal (hereinafter, called the “parallel signal”), and the signals are transmitted through a plurality of lines.
In addition, a communication system in which a signal is communicated by the serial transmission system is herein called the “serial communication”, and on the contrary, a communication system in which a signal is communicated by the parallel transmission system is herein called the “parallel communication”.
On the one hand, there is known a lens apparatus capable of communicating a signal with a camera body through both systems of the serial communication and the parallel communication so that the lens apparatus can communicate with any of camera bodies which may have only the serial communication system, only the parallel communication system or both of them (see Japanese Patent Application Laid-Open No. 11-98198).